What is atmospheric pressure at sea level expressed in PSI?

Atmospheric pressure at sea level is commonly defined to be approximately 14.7 PSI (pounds per square inch). This value represents the pressure exerted by the weight of the air in the atmosphere at sea level, which is a standard reference point used in various scientific and engineering calculations, including plumbing.

At sea level, the atmosphere presses down with this specific pressure, and understanding this value is crucial for plumbers when measuring the pressure in systems or ensuring that pressure gauges are calibrated correctly. This standard is based on the average conditions and can vary slightly depending on local weather, temperature, and altitude changes. By knowing that atmospheric pressure at sea level is 14.7 PSI, you can accurately calculate pressures in plumbing systems, assess the functioning of water and gas lines, and make informed decisions based on pressure readings.

The other options do not accurately represent atmospheric pressure at sea level, highlighting the importance of familiarity with this standard measurement.